The present invention relates to a decorative laminate using thermosetting resin and a manufacturing method therefor.
Decorative laminates can provide various surface shapes, colors, glosses and volumes resembling wood, enamel, pottery, tile, cloisonne ware, natural stone and so on, and they are widely used as raw materials for furniture and building materials. These kinds of decorative laminates are manufactured by impregnating a printed decorative sheet having a printed wood grain or a printed enamel pattern with a thremosetting resin; laminating the printed decorative sheet with core papers, an overlay paper or the like; and hot-pressing the laminated body using a predetermined embossing press plate.
For forming a three-dimensional pattern or a roughened surface for reducing gloss, methods have been proposed such as embossing using an etched or sand blasted metal press plate. However, the procedure for manufacturing such a metal press plate is complex, and the derived metal press plate is extremely expensive. Thus, it has been general practice to manufacture resin press plates using a metal press plate as an original, and to use these resin press plates for actual embossing. However, a resin press plate of, for example, phenol resin or epoxy resin is defective in that a release sheet must be used to prevent adhesion between the plate and the decorative laminate. Its durability has not been satisfactory, either. Further, for various decorative laminates of thermosetting resin, a printed decorative sheet is used which has a printed pattern of an abstract pattern, wood texture, stone grain, a pattern of brick or ceramic, or various other patterns. Even when this printing is very fine, the design of the decorative laminate may not be satisfactory if the resin layer at the surface of the decorative laminate does not have a three-dimensional pattern or a gloss which goes well with the printing. Especially in the case of wood grain patterned decorative laminate, it has been difficult to completely align the part of the printed decorative sheet representing the xylem vessels (hereinafter called the tracheal part) with the recess formed by embossing. For manufacturing this kind of decorative laminate, a so-called wiping method is known according to which a decorative laminate is molded using a press plate with a three-dimensional pattern formed by etching the surface of a metal plate such as stainless steel, then the recess of the derived decorative laminate is painted with ink for coloring the tracheal part. However, with this method, it is extremely difficult in practice to select an ink which strongly adheres to the surface of the decorative laminates and which still presents the other required properties. For example, even when a transparent resin is coated over the ink layer for protecting the ink layer, it is very difficult to obtain the original surface conditions and properties of the decorative laminate of thermosetting resin. Further, in a metal press plate manufactured by etching or sand blasting, the inclination of the protruding and recessed parts is sharp, the protruding part is generally smooth, and the recessed part is rough. Thus, decorative laminates manufactured using such a metal press plate have been defective in their reproduction of the surface of the enamel and the natural materials.